The present invention relates to the storage of spent nuclear fuel, and in particular to apparatus employed to consolidate fuel rods after removal from the fuel assembly frame structure.
For a variety of reasons, the disposal, reprocessing or storage of spent nuclear fuel assemblies has been impossible, or very difficult, for the operators of nuclear power plants. As a consequence, efforts have recently been directed toward consolidated nuclear fuel storage, by which the individual fuel rods are removed from spent fuel assemblies and stored in a tightly packed array until ultimate disposal methods are approved by the regulatory agencies.
In co-pending U.S. patent application Ser. No. 535,105, "System and Method for Consolidating Spent Nuclear Fuel", filed Sept. 23, 1983 and assigned to Combustion Engineering, Inc., apparatus is disclosed for removing fuel rods from two fuel assemblies and consolidating the rods into an area equivalent to one fuel assembly. The consolidation is implemented at three stations, one of which includes an interim fuel transfer canister where the fuel rods are rearranged from a relatively loosely packed rectangular array into a relatively tightly packed triangular array. This is accomplished by inserting the rods between long flat plates, portions of which are contained within a funneled canister having a tilted base. The canister walls, variation in plate lengths, and tilted base, tend to force the fuel rods into the desired final array.
It has been found that the transfer canister described in the foregoing application does not provide sufficient guidance to individual fuel rods to permit the degree of trouble-free canister loading that is desired. Accordingly, a need was recognized to improve upon this prior canister design.